1. Field of the Invention
This invention relates to a method and apparatus for developing a processless electron recording medium (PERM) using an ultraviolet laser beam.
2. Description of the Prior Art
PERM is a laminated transparent film consisting of an electron sensitive layer that is adhered to a transparent conductive layer on a polyester base. It was developed by the GAF Corporation as a processless electron recording medium that can be used for extremely high resolution image production. Recording is accomplished by a modulated and rastered electron beam (e-beam).
A prior art e-beam system used to record on PERM is illustrated in FIG. 1. The essential components include a triple-differentially-pumped vacuum chamber, an electron gun, electromagnetic focusing and deflecting coils, and a film transport system. An electronic signal is input to an electron gun 2 that is maintained in a 10.sup.-7 Torr high vacuum environment by a stage one vacuum system 4. A beam of electrons that pass through an orifice from stage one is focused by electromagnetic coils 6 into the deflection yoke 8 where it is electromagnetically rastered onto the surface of PERM. The focusing and rastering is carried out in a 10.sup.-5 Torr vacuum by the stage two vacuum system 10. A mechanical scroll 12 transports the PERM 14 in a third vacuum chamber that is maintained at 0.1 Torr by the stage three vacuum system 16.
There are several disadvantages to the use of this method and apparatus. First, the e-beam development of PERM is complex. The system shown in FIG. 1 requires a triple-differentially-pumped vacuum using diffusion pumps and cryogenic traps. In addition to its complexity, the e-beam process requires the addition of a costly transparent conductive layer to the PERM film to dissipate electric charge. This increases the cost of producing PERM more than 25 percent. Finally, the e-beam system is capable of producing only blue coloration in PERM.
It is therefore an object of the present invention to develop a less complex process that is free of vacuum constraints for recording on PERM.
It is also an object of the present invention to develop a PERM recording process that is competitive with the speed with which electron beams record on PERM.
It is yet another object of the present invention to make possible a PERM developing process that can record in either red or blue coloration.